1. Field of the Invention
This invention is concerned with preventing overpower damage to the receiver portion of a transceiver in the presence of an electromagnetic pulse (EMP) or lightning, and more particularly, to preventing damage in transceivers having a combined input/output antenna port.
2. Description of the Prior Art
Radio frequency transceivers utilizing a common transmit and receive antenna port may be damaged by an input signal which is at a high power level. If one attempts to provide power limiting means to prevent damage to the receiver portion of the transceiver, the same limiting would apply to the transmitter and thus the transmitter output power also would be undesirably reduced.
If the transceiver is of the type which has two output ports, one coupled to a transmitter antenna and one coupled to a receiver antenna, then it is possible to put a limiter in the receiver path. U.S. Pat. No. 3,309,698 issued on Mar. 14, 1967 to G. S. Baldock is an example of a radar having separate receiver and transmitter antennna connections marked Tx and Rx in the various figures and has limiters 12 and optionally 12.sup.1 in the receiver path. A solution such as disclosed in U.S. Pat. No. 3,309,698 is not possible in a transceiver having a combined receiver and transmitter antenna port.